Wellington rat census reveals rodents are on the rise, but the city is fighting back

Thursday, 17 May 2018

All Wellington suburbs now have a predator free group.

Wellington's war on rats is teetering on a knife edge.

Results from the capital's annual rat census show rodent numbers have increased by five per cent, and local trapping groups are under pressure to hold the line.

The battle is being waged on the Miramar Peninsula, which is hoped will become the city's first predator free area. It was there that the rat population was counted in March.

'We're not living or dying on the strength of the census, we're just trapping and smashing rats left right and centre,' Predator Free Miramar founder Dan Henry said.

Dan Henry, founder of Predator Free Miramar, with the peanut butter that rats love.

* Watch out Wellington, the rats are back

* Capital pests prefer peanut butter on their traps**

Miramar residents are already noticing an increase in native bird numbers, Dan Henry said.

The census involved 281 peanut butter-covered chew cards placed in a grid across the peninsula and left for three nights.

Ninety five per cent of the cards were recovered, up from 91 per cent in 2017, with the most rat chews found on the coast. Increases were also seen in urban areas where rats have easy access to food.

Two cards showed evidence of stoats, down from six last year, but mice chews were found on nearly half of all cards.

Henry said rodent numbers had increased of late, and previously-empty traps were suddenly full.

'It's gross and appalling at the same time as being really quite exciting.'

The Miramar group was about to celebrate its one-year anniversary, and had trapped 1996 rats, mice and hedgehogs so far.

'That five per cent increase isn't a knock. To me it says 'imagine what it would be if we weren't doing what we were doing'.'

Greater Wellington Regional Council's environmental scientist Dr Philippa Crisp said the hot summer and warm autumn meant the city could have expected a greater rise in rat numbers.

'That we haven't is probably a sign of the success of Miramar's backyard trappers, who have grown in number and enthusiasm over the past year,' she said.

'They are almost holding the line, but this year's results shows the challenges faced in keeping rat numbers down over time.'

Predator Free Karori is the biggest pest-catching group in the country and spokeswoman Kate Fitzgerald said there had been a peak in rats caught across the suburb recently.

'We've had 800 catches since October, and also have a few situations where people have rats in their compost that are the size of chinchillas.'

Like Hendry, she was not disheartened by the census results and believed a predator-free future was still on the cards.

'If the commitment is there, and we can keep at this lark, it will happen.'

WELLINGTON'S WAR ON PESTS

* The city has 23 backyard resident groups currently trappings pests. Almost every suburb is covered.

* About 40 community groups actively trap in the city's reserves and 80 community groups are working in the broader ecological restoration space.

* The Miramar Peninsula has been free of possums since the mid-2000s. About 650 households in Miramar and Seatoun are participating in backyard trapping.

* Predator Free Miramar has just celebrated its 900th catch.

* Predator Free Karori, with 700 trappers, is New Zealand's largest Predator Free community.